The World Health Organization gave a green light to the use of experimental drugs to combat the Ebola outbreak in West Africa, with demand for—and questions about—untested treatments growing after two infected Americans received some.

A panel of ethicists convened by the WHO said on Tuesday that it is ethical to use the treatments given the size of the outbreak, which has killed at least 1,013, and the challenges of controlling it through regular measures that have stopped other Ebola outbreaks.